Parents

Henoch-Schönlein Purpura (HSP)

At first, Tyler developed red patches and raised spots that turned purple and looked like bruises all over his legs and buttocks. Then he complained that his stomach and knees hurt. When his parents took him to the doctor to find out what was wrong, the doctor said that Tyler had the classic signs of Henoch-Schönlein purpura.

About Henoch-Schönlein Purpura

Henoch-Schönlein purpura (HEH-nok SHOON-line PURR-puh-ruh) — usually just called HSP — is a condition that causes small blood vessels, to become swollen and irritated. This inflammation, called vasculitis, usually occurs in the skin, intestines, and kidneys. Inflamed blood vessels in the skin can leak red blood cells, causing a characteristic rash called purpura. Vessels in the intestines and kidneys also can swell and leak.

The disorder was named after two German physicians, Eduard Henoch and Johann Schönlein, who first described the disease in the 1800s. Sometimes it's also called allergic purpura or anaphylactoid purpura.

HSP occurs much more often in kids than in adults, usually between ages 2 and 11. It is one of the most common forms of vasculitis in children, and boys get it about twice as often as girls.

Causes

Although no one really knows what causes HSP, doctors do know that it occurs when the body's immune system doesn't function as it should. A protein called immunoglobulin A (IgA), a type of antibody, is deposited into the blood vessels and seems to be connected to their inflammation.

It is unclear why this immune reaction occurs, but in many cases, it seems to be triggered by a bacterial or viral infection of the upper respiratory tract (sinuses, throat, or lungs). Although less common, other triggers have been identified, such as certain medicines, food reactions, insect bites, and vaccinations.

Signs and Symptoms

Common signs and symptoms of HSP include:

purpura, the raised, reddish purple rash

joint pain and swelling

stomach pain

blood in the urine (pee) or other kidney problems

fever

headache

The rash occurs in almost all cases and is usually what helps doctors diagnose HSP. It may take the form of pinpoint red dots (called petechiae), bruises, or sometimes blisters. The rash usually occurs on the legs and buttocks, but can also appear on other parts of the body, such as the elbows, arms, face, and trunk.

Most kids with HSP also have joint pain and swelling. These symptoms can happen before the rash appears. They most commonly affect large joints, such as the knees, ankles, and elbows, but the hands and feet can be affected.

Stomach pain usually starts a week after the rash appears. Pain is intermittent and can be accompanied by nausea, vomiting, or diarrhea. Some kids will have blood in the stool (caused by leaky blood vessels), but it may not be visible.

HSP can affect the kidneys. Small amounts of blood or protein might be found in the urine, which occasionally can be bloody.

Diagnosis

When the characteristic rash on the legs and buttocks is present, especially if accompanied by abdominal or joint pain, doctors can easily diagnose HSP. A diagnosis may be more difficult if joint pain or abdominal symptoms are present before the rash appears, or if symptoms take several weeks to show up. To help make the diagnosis, the doctor may recommend a skin biopsy.

The doctor also may request routine blood tests to look for signs of infections, anemia, or kidney disease. If abdominal pain is severe, imaging tests (like X-rays or ultrasound) may be needed. A stool sample can check for blood in the stool (poop). A urine sample can reveal blood or protein in the urine.

Up to half of kids who develop HSP will have complications with their kidneys, so the doctor will probably check kidney function over several months. If the doctor suspects that HSP has caused kidney damage, your child may need to see a kidney doctor (nephrologist).

Also, the doctor may tell you to stop giving your child certain medications if there's a chance that they caused the HSP.

While at home, try to keep your child as comfortable as possible. Be sure your child gets plenty of rest and drinks fluids. If your child stops eating or drinking, or develops severe abdominal pain or kidney problems, hospitalization might be necessary.

Outlook

Most children with HSP fully recover within a month and have no long-term problems. Kids whose kidneys are affected will need to see a doctor for regular checkups to monitor kidney function.

About one-third of those who have HSP get it again, usually a few months after the first episode. This (along with chronic kidney problems) is more common in older kids and adults. If HSP does come back, it's usually less severe than the initial episode.